Nucleic acids of Moloney sarcoma virus (MSV) have been fractionated into subcomponents and used to detect virus-specific RNA in subcellular fractions of transformed cells. In addition, viral proteins have been detected in these fractions by SDS-PAGE after immunoprecipitates with antiserum prepared against MSV. In vitro synthesis of MSV specific proteins has been accomplished using RNA purified from subcellular fractions. BIBLIOGRAPHIC REFERENCES: Vande Woude, G. F., Robey, W. G., Oskarsson, M. K., Haapala, D. K., Fischinger, P. J., Naso, R. B. and Arlinghaus, R. B.: Properties of Moloney sarcoma virus specific p60 and its detection in transformed cells. In Clemmesen, J. (Ed.): Bibliotheca Haematologica No. 43. Basel, Switzerland, S. Karger AG, 1976, pp. 125-127. Robey, W. G., Oskarsson, M. K., Vande Woude, G. F., Naso, R. B., Arlinghaus, R. B., Haapala, D. K. and Fischinger, P. J.: Cells transformed by certain strains of Moloney sarcoma virus contain murine p60. Cell 10: 79-89, 1977.